The recessed luminaries with parabolic louvres, which one finds in the marketplace, are made of a metallic base on which all the necessary electrical components are placed, and a grid of parabolic reflectors—either diffusive or catoptrical—which concentrate and focus the light. This grid is placed into the metallic base of the luminary. The reflection grid, consisting of parabolic louvres, is made of individual elements of different shape, which are interconnected and thus compose a uniform cellular network. The parabolic louvres, which are deployed in the luminaries for false, and solid, ceilings and are presently in the international market, are mainly (90%) constructed of a thin aluminum sheet of at least one reflecting surface, either catoptrical or diffusive.
The support base for the electrical components of all the known models of fluorescent luminaries for false ceilings available today is completely made out of iron sheet, which, through proper cuttings and formations, reaches its final and desirable shape. The shape of the metallic base of the luminaries for false ceilings is a box-like housing of approximately 10-cm depth which is open on its upper side. The shape of this box, seen from an upper view, is either a perfect square or a rectangular parallelogram of minimum dimensions 10×60 cm and maximum dimensions 62×160 cm. The forming of the iron sheet into boxes of such dimensions, and especially the construction of the four sidewalls of the base, is achieved by many different shaping phases. This process increases considerably the production cost of the metallic support base for the electrical components and, consequently, the final price of the parabolic luminary for false ceilings. One of the shaping phases followed by most manufacturers that increases considerably the time and cost needed for construction of the base is the welding or the riveted jointing of the side walls of the base at the four side edges of the square or rectangular box so as to achieve steadiness and binding of the box. Furthermore, the sole use of iron sheet for the construction of the base results in making the end product quite weighty. Another consequence of this is the unnecessary weight to be carried by the false ceiling. It is also difficult to handle the product during its production process as well as for the electrician to install it due to its weight.
The grid of the parabolic reflectors of the fluorescent luminaries for, solid and false, ceilings is a net of elements of different shapes, which are mainly constructed of thin aluminum sheet, which has at least one catoptrical or diffusive surface. First of all, this grid consists of a square or a rectangular frame, which is formed by four linear elements joined together at the four corners. The main parabolic components, which are to reflect and focus the light, are proportional to the number of lamps of the luminary and are fixed in the two opposite sides and at the inner part of the frame. At the other two sides of the frame and vertically towards the main parabolic components, the elements of the parabolic or non-parabolic transverse blades are placed, thus making it possible to create a reflection grid. This grid, besides concentrating and focusing the light, is also useful in blocking the view of the fluorescent lamps of the installed luminary from an observer, who sees the luminary from a certain angle. The dimension of the angle from which the fluorescent lamps are not visible depends on the quality of the louvres and turns out to be one characteristic feature of recognition which distinguishes the parabolic fluorescent luminaries for exposed, and false, ceilings from any other and classifies them into different categories.
In all parabolic fluorescent luminaries for solid, and false, ceilings known until today, in order to replace the lamps or the starters, the louvre made of the cross blades described above has to be removed beforehand so as to gain access to the lamps and the starters. In order that the grid of the reflectors (louvre) could be removed without being blocked by the fluorescent lamps of the luminary, the transverse blades of the grid have openings along their entire length. This means that they are placed exactly underneath the fluorescent lamps so as to overcome the obstacle of the installed lamps upon the removal of the reflection grid. The fact that there is no parabolic reflective surface underneath the fluorescent lamps is the cause for part of the light output which is diffused from the lower part of the lamps being directed towards the flat surface of the metallic base of the luminary and not spread uniformly, therefore not being concentrated and focused properly towards the floor. This would not have been the case if there were a continuous parabolic reflector underneath the fluorescent lamps.
There are sections of the metallic base that are not covered by the reflection grid and these sections serve as light reflection surfaces. Since these sections are visible to the observer, the manufacturers have to paint the whole iron sheet base for the support of the electrical components in white color. This results in an even higher production cost of the luminary in question.